Ben Simmons chalked up his 21st double-double of the NBA season but it wasn't enough to prevent Philadelphia from slumping to back-to-back defeats without injured star Joel Embiid.
Hosts Indiana fought back from a nine-point half-time deficit to down the 76ers 101-95 and leapfrog above them to fifth in the eastern conference standings.
Simmons was electrifying in the opening half on Monday, dunking his way to 20 points and nine rebounds as the visitors led 49-40.
And despite finishing with a game-high 24 points and team-high 14 rebounds, the Australian star's influence was minimal in the second half.
Like they did in Dallas, Philadelphia struggled in the second half and failed to close out another game as they slipped to 1-2 without Embiid (finger).
In the loss to the Mavericks, Simmons followed up a dominant first half with zero points after the main break.
The Pacers (25-15) have now beaten the 76ers (25-16) twice in a fortnight, this time after charging back from an 11-point deficit in the third quarter.
Malcolm Brogden and TJ Warren had 21 points apiece for the Pacers, who also got 10 points and 16 rebounds from Domantas Sabonis.
Elsewhere, Jayson Tatum scored 21 points and Jaylen Brown chipped in with 19 to lead Boston to a 113-101 win over Chicago.
The Bulls sputtered to a seventh loss in eight games despite a game-high 30 points from Zach LaVine.
In Detroit, Lonzo Ball scored five of his 17 points in overtime to lead New Orleans to a 117-110 overtime victory over the Pistons.
The depleted Pelicans were without Brandon Ingram, Jrue Holiday and JJ Reddick, Zion Williamson, and Derrick Favors.
Williams, last year's No.1 draft pick, is scheduled to make his long-awaited NBA debut later this week against Joe Ingles' Utah.
Shai Gilgeous-Alexander had 20 points, a career-high 20 rebounds and 10 assists in his first triple-double as Oklahoma City beat Minnesota 117-104.
In Sacramento, Orlando forward Aaron Gordon made a three-point play with 1.1 seconds remaining to seal a dramatic 114-112 win over the Kings.
Damien Lillard had 30 points, including a buzzer-beater from near halfcourt at three-quarter time, to lead Portlead past Charlotte 115-112.
And in the final game of the day, LeBron James scored 23 of his 31 points in the second half of the Los Angeles' Lakers' 128-99 victory over Cleveland.
It was the Lakers' nine consecutive victory.
Australian Associated Press